Most likely, he is just stomping away a fly. However, you need to see the whole picture. Body language can be tricky because the same action doesn't always mean the same thing. Watch the rest of his body language and take into account the situation. If his ears are pinned and he's all tensed up, stomping with a back hoof could be a warning to a kick. If you're trying to pick up his feet, he might stomp them down to get away from you. He'll show you what he means.
Chat with our AI personalities
If a horse stamps his back feet on a regular basis it could be mites, worming can sort this out (ivermectin) or try spraying the area with frontline spray, or a louse powder.
If a horse stamps its front feet it usually means he is angry and wants you to leave him alone.
He could also be shaking off flies on his legs and/or belly.
Stomping of the back legs can mean several things.
1. The horse could be attempting to dislodge a fly or biting insect.
2. The horse is uncomfortable or in pain and may be attempting to relieve stress/ pain.
3. The horse could be trying to warn another horse , animal, or person that they are too close and are about to get kicked.
sometimes it has fly's on it's legs or it is about to kick if it does not have fly's on it's legs i would step a way or go to thefront of your horse and pet it to calm it down'